


Big Girl Panties

by Anonymous



Category: Original Work
Genre: Alpha/Beta/Omega Dynamics, Alpha/Omega, Dubious Consent, F/F, Female Alpha, Female Omega, Knotting, Loss of Control, Loss of Virginity, Mating Cycles/In Heat, Mother-Daughter Relationship, Underage Sex
Language: English
Status: Completed
Published: 2020-02-24
Updated: 2020-02-24
Packaged: 2021-02-27 23:55:49
Rating: Explicit
Warnings: Underage
Chapters: 1
Words: 2,978
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/22874371
Author URL: https://archiveofourown.org/
Summary: When a 12-year-old omega girl goes into her first heat, her alpha single mom is stuck giving her The Talk... and helping her through.
Relationships: Alpha Mother/Underage Omega Daughter
Comments: 12
Kudos: 175
Collections: Anonymous, Kissing Cousins Flash Exchange





	Big Girl Panties

**Author's Note:**

  * For [eidetic](https://archiveofourown.org/users/eidetic/gifts).



"Mom?"

Diane looked up, frowning, from the tax paperwork spread out over the dining table. There was an odd tone in Ava's voice. "What is it, honey?"

Her daughter approached her and timidly held out a pair of slick-sodden underpants.

Diane's nose understood immediately: it smelled _omega in heat_ and sent urgent signals through her body. Her clit stiffened uncomfortably inside her boxers and her nipples tightened against her terrycloth robe. Then her brain caught up and she felt a wave of shame... which did nothing to diminish her arousal at the thought of her sweet, shy 12-year-old in heat. She'd always liked shorter, younger omegas, though not usually a full foot shorter. Or an entire generation younger.

But she had to be Mom now, not a horny alpha who'd been high and dry for way too long. "Oh, honey," she said, "come here." She half-turned in her chair and wrapped Ava in a hug, glad the awkward angle hid her hard-on. "Hey, my big girl. Congratulations."

Ava half-laughed against her shoulder but was clearly close to tears. "Mom, I'm not ready for this! I thought it wouldn't happen until I was 13! I think I'm the first one in my class!"

"Oh, baby, it's okay. Every body's different, you know." Diane hugged her again and then leaned back to give her a patented Mom Means It look. "There's nothing wrong with you, and this doesn't change anything. Your friends won't care. You're just an early bloomer."

"Do we have any... any pads or anything?"

"I don't think so," Diane said. "I guess I should have stocked up, but who knew this was coming, right? I'll buy some tomorrow, and a bottle of evening primrose oil."

"I can get my own," Ava said staunchly. "You don't have to brave the estrus products aisle for me."

Diane was startled into a belly laugh. "That is the alpha stereotype, isn't it? But I've bought pads for your father plenty of times. It's not a big deal."

Ava rubbed her hand over her eyes. "I wish Dad were here."

That hurt, but Diane understood. Ava's omega parent should be the one guiding her through this change in her body and her life. "I do too," she said honestly, though most of the time Rick being deployed overseas made her life easier, not harder. "But you've got me, and I'll do my best. How are you feeling?" She tried to remember what Rick had wanted back when he had heats. He'd been on suppressants for most of a decade, since they'd decided one kid was enough. "Are you warm? Your dad usually liked to eat a lot of ice cream."

"Ugh, yeah, I'm sweating like anything. Ice cream sounds great. And, um, would it be okay if I got undressed?" Ava bit her lip. "I can stay in my room—"

"I washed your butt enough times when you were a baby, I think I can stand to see it now," Diane said with a smile she didn't feel. The last thing she wanted was to see Ava naked and dripping slick. But what was most important was making Ava feel comfortable. 

Ava sighed with relief and pulled off her nightshirt. Diane hurriedly closed the curtains and went to get a towel for Ava's chair.

Ten minutes later, as Ava scraped up the last drops of Rocky Road, Diane was deeply aware that she had made a strategic error. Even with the towel, Ava's slick was puddling under her, and its sweet-tangy scent swirled in the still air. Diane couldn't open a window while her pre-teen daughter was walking around naked, and the building manager kept not getting around to fixing their air conditioner. She tried to breathe shallowly, but every whiff of pheromones and delicious omega ripeness went straight to her groin.

Ava's face was flushed and her own breaths were deep and rapid, not quite hyperventilating. She absently caressed her sides, massaging her sweat back into her skin. Her small breasts rose and fell as she shifted in her seat, and Diane realized she was rubbing herself against the rough texture of the towel. Diane looked away, desperately trying to think about taxes or baseball statistics or anything that wasn't seeing her daughter as a sexual being. _Ava's not the only one who's not ready for this,_ she thought.

"Mom," Ava whispered. "I feel so weird. What's happening?"

Oh, this was not how she'd wanted to have The Talk with her daughter. She felt a flash of tired, familiar rage at Rick for dumping this on her, like so many other things. "Your body thinks it's ready to make a baby," she said awkwardly. "It... it's doing things that make that more likely to happen, like, uh, making pheromones that can attract a partner, and..." She had no idea how to say this in an age-appropriate way. Ava's body thought it was an adult, but Ava was still a child. "And making it physically... easier... for an alpha to get you pregnant."

Ava's face went a deeper shade of red and she stood up abruptly. "I think—I'm going to my room!" Before Diane could say a word, Ava fled down the short hallway.

Watching her go, Diane had a sudden memory of the night she and Rick conceived Ava, a lush and wild orgy of two that left them both slick-soaked and giddy with hope. She smiled, remembering the wonder of watching his belly swell a few months later. She wished she'd been able to say something to Ava about how transcendent heat sex could be with the right person at the right time. Her clinical and vague description had left out all the important parts. She hoped she hadn't scared the child. Of course they'd have to put Ava on suppressants for now, but someday, with a loving partner, she should get to enjoy heat to its fullest.

That thought led to picturing Ava naked and glowing with one hand on her rounded abdomen, a notion that ought to give any mother hives. It was the 21st century; no one wanted their little omega getting pregnant at 12. But the image in Diane's mind was so beautiful, and so intensely erotic, that she had to put her head down on the table for a moment. All her alpha instincts were on high alert. _Omega in heat. Fertile, young, healthy. Put a baby in her right now._ Her body couldn't care less that the fertile, young, healthy omega was her own child.

Then Ava started masturbating.

Not for the first time, Diane wished their apartment were bigger than a shoebox. All her senses were sharpened, and she could clearly hear gasps and whimpers and bedspring squeaks through Ava's closed door. She knew she should go into her own room and put on music, or sit in the bathroom with the shower running for white noise. But she stayed where she was, listening, disgusted with herself but unable to pull herself away.

After a particularly desperate whine, her self-control splintered. She grabbed the wet towel from Ava's chair and pressed it to her face, sniffing and licking it. She'd always loved slick and couldn't understand why some alphas were squeamish about going down on omegas. The slippery, almost gooey fluid slid over her tongue, filling her mouth with the familiar salt-citrus taste, and she moaned. How long had it been since Rick had opened himself to her that way? Years. Too many years. And, oh God, Ava's slick tasted just like Rick's.

Gasping, she yanked open her robe and slid her hand into her boxers. Her sweaty hand was too rough, so she gathered a palmful of slick—of her daughter's slick, and by now the rush of shame was almost indistinguishable from the rush of arousal—and rubbed it over herself, working her sheath over her engorged clit. Her knot twinged and she sobbed into the towel, knowing no self-given orgasm could compare to knotting an omega, _her_ omega, her omega was in heat and needed her, her omega _needed her_ —

Diane was already out of her chair and halfway down the hall when Ava yanked open her bedroom door, wailing. "Mom, help, it's not working, nothing's—Mom?"

"I'll help you," Diane said hoarsely. "It's okay, baby. I'll help."

She shrugged off her robe and let it fall in a heap next to the discarded towel. Ava's eyes widened at the sight of Diane's tented, slick-smeared boxers, and she took a step backward. Diane followed her, shoulders down, not prowling—there was no need, this was _her omega_. (Her daughter. Her daughter. But that scent had said _her omega_ for 15 years and there was no telling her body otherwise.)

Ava backed up against the bed. Diane pressed against her and bent down to kiss her neck, scenting her deeply. The poor omega was so nervous. First heats could be hard and scary. "I'm here," Diane said, lapping at Ava's sweaty skin and tasting salt and heat and slick and fear and need. "I've got you."

Ava moaned and toppled back onto the rumpled sheets, one hand going between her legs. "Nothing I do makes it better!" She whined and tossed her head.

"Your body wants to be knotted by an alpha," Diane said gently. "Just rubbing at yourself won't... won't do it." 

Ava shook her head. "No, I tried—it didn't—" She dug around in the sheets with her free hand and came up with a cheap latex dildo, the sort where you had to squeeze a hand pump to inflate the knot.

"Where on earth did you get that?" Diane said. She was a little startled that her 12-year-old had bought sex toys—maybe this heat hadn't come out of nowhere after all—but mostly upset that Ava had resorted to something so shoddy. "Honey, that's for betas who want to play alpha. It's not going to do a thing for you."

"Then what do I do?" Ava's voice rose desperately.

Diane gazed down at her, seeing the child she'd loved from birth and would protect with her life, and also seeing a lithe, ripe omega flushed with heat and reeking of that so-familiar slick, the scent that cried _yours yours yours_. She made one last effort to stop herself, and utterly failed.

"You just relax," she said, crawling onto the bed and gathering Ava into her arms. "I'm going to take care of you."

Ava flinched at the feeling of Diane's hard clit pressing up against her leg. "Are... are you sure... this is okay?"

"I'm sure," Diane said, because she was. She knew she was about to fuck her daughter and that was terribly wrong, but on a deeper level, she was an alpha about to knot her omega in heat, and nothing could be more right. "I'm an alpha and you're an omega, and your body needs an alpha knot to feel better. And I'm your mom and it's my job to take care of my baby."

"O-okay." Ava took a deep breath. "B-but I'm scared."

"I've got you," Diane said tenderly. "I'll help you feel so good."

She let herself run her hands over Ava's body, marveling at the soft skin and gentle curves. She'd never been intimate with a female omega before, never even really thought about it, and it was unexpectedly exciting to cup Ava's small breasts and lick at the sweaty valley between them. She thumbed Ava's nipples and the girl moaned and relaxed against her, trusting her.

Diane slid down to kneel between Ava's legs and lowered her head to drink directly from Ava's cunt. Ava squeaked and bucked, and more slick gushed out over Diane's face. She lapped it up, feeling almost drunk on it. That irresistible, lemony scent filled her nose and made her head spin. 

She ran her tongue over Ava's little omega clit, but the omega shook her head rapidly, a whine catching in her throat. "In me," Ava begged, "please, in me, please, please..."

There was no denying her. Diane guided Ava onto her belly and helped her lift her hips into a classic presenting position. She kicked off her boxers, glad that Ava couldn't see her clit—it was bigger than most, and even a little one would probably look scary to a nervous young omega, with its pointed tip and the small bulge hinting at the knot to come.

All her instincts demanded that she thrust right in, but she gritted her teeth and said, "I'm going to start with my fingers, okay? I want to make sure you're ready."

"I'm _ready_ ," Ava cried into her pillow, and Diane's clit jumped. She'd meant to start with one finger, but Ava was so open and slick that she couldn't help sliding two fingers right into the welcoming warmth, savoring her daughter's wordless cry of pleasure and need. 

Oh, her girl was tight! She'd never felt an omega this tight. The virgin hole almost sucked at Diane's fingers, as snug as if Ava were already coming. As Ava pushed back against her hand, Diane wondered whether she should just use her fingers—she'd fake-knotted Rick with curled knuckles before. But then she remembered that never worked during heat. An omega's body knew whether it was taking a real knot, and it couldn't easily be fooled.

She began working her fingers gently in and out, angling to press against Ava's O-spot before remembering females didn't have one. But there was a larger, softer bump deeper in—the girl's G-spot, Diane realized. She caressed it from the inside as she reached down with her other hand to rub Ava's clit, and was rewarded almost instantly by Ava gasping "Oh—oh, what—Mommy— _ohhh_ —" and losing herself in a shuddering orgasm. Slick poured over Diane's hand as Ava's cunt clenched around her fingers.

Diane wondered whether it was Ava's first orgasm ever. She felt a swelling of maternal pride even as her clit twitched hungrily, a thread of precome sliding down from its tip.

As Ava slumped on the bed and relaxed, Diane knew there would be no better time. She withdrew her fingers and slathered her clit in slick, hissing as she rubbed its sensitive head. Her sheath was fully retracted, her clit swollen and dark and eager. She caressed Ava's back reassuringly. "Here comes my clit now, honey," she said. "Just relax and let me in."

She grasped Ava's slim hips, drew them up high, and slid her clit into her omega's waiting cunt.

Ava nearly levitated off the bed, wailing, as Diane thrust in again and again, deeper and deeper, trying to go slowly but unable to help herself. It had been so long, so fucking long, and Ava was so slick and tight and _hot_. Drops of sweat glistened on her back and then flew everywhere as Diane began to fuck her in earnest, their bodies slapping together. Ava was so small and slender that Diane could use her as a sleeve, not so much thrusting as working Ava's hips back and forth so the omega's slick hole stroked her clit. It was sublime, the best thing Diane had ever felt. She knew there'd be no going back after this—only her daughter's sweet, tight, eager cunt would do.

Diane couldn't even tell whether Ava was crying out in pain or pleasure until she felt Ava start to come around her again, squeezing her clit with a devastating rhythm. Her knot started to swell. "Fuck, baby, I'm gonna—gonna knot you," she growled. "You ready?"

"I'm ready, Mommy, _please_ ," Ava sobbed, grinding back against her. "I need it so much, please!"

Diane pulled Ava's hips back against her and groaned as her climax swept through her. Her knot swelled to lock the two of them together, trapping her seed inside. Ava instinctively responded by going limp and yielding, moaning as Diane's hot come pumped into her. Diane rubbed Ava's lower belly tenderly, feeling her pubis tighten and swell as come filled her plugged-up cunt. "Good girl," she said. "So good, my good girl."

At last there was nothing to do but wait for her knot to go down. She managed to get them onto their sides, big spoon and little spoon, without tugging too much at where they were joined. "You okay, honey?" she asked softly.

Ava shifted against her a little. "Kinda sore, I think? But I feel so much better now." She sighed. "Thanks, Mom."

 _I just knotted my daughter,_ Diane thought. _My daughter who's in heat. I could have gotten her pregnant._ She knew she should feel bad about it, and she waited for the guilt to wash over her, but it never came. All she felt was post-orgasmic bliss and deep gratitude that her daughter trusted her enough to come to her in distress and accept her help.

 _God, what if she'd gone into heat at a friend's house, or some random alpha on the street had gotten a whiff of slick?_ Diane tightened her arms around Ava protectively. Maybe fucking her daughter was not... ideal. But all the alternatives were so much worse. Ava was both her daughter and her omega now, and Diane would never, ever let anything bad happen to her.

Soon she'd have to tell Ava that heats lasted for days, sometimes even a week, and they'd need to knot at least once a day to keep the symptoms in check. Soon they'd have to talk about how this part of their relationship absolutely was not a thing Ava could tell anyone about—not her best friend, not Rick, no one. But for now there was just her sweaty, happy daughter dozing in her arms, more cuddly than she'd been in years. Diane kissed the top of Ava's head and decided that everything else could wait.


End file.
